1. Field of the Invention
This invention relates to a vehicle seat in which the position and gradient of the seat can be automatically adjusted according to the preference of the seat occupant. More particularly, this invention relates to an improved vehicle seat equipped with an automatic adjustment mechanism capable of adjusting and controlling the height of the seat level, the gradient of a headrest positioned on the seat back, the thigh support of the seat and the mobility of the seat body in a longitudinal direction.
2. Description of the Prior Art
It is known in the art to provide vehicle seats having automatic mechanisms, such as an inflating mechanism for the contours of the seat, an elevating mechanism for the level of the seat and a mobilizing mechanism for the movement of the body of the seat in a longitudinal direction. Typically, these known mechanisms are driven by utilizing the stroke of a cylinder, such as a hydraulic cylinder, an air cylinder, or motordrive cylinder. The cylinders are controlled by a remote control on the dashboard. It is known that the inflating mechanism for the contours of the car seat can consist of an inflatable air bag. The bag is housed within the cushion of the seat contour and is actuated by a pneumatic means. However, the use of the air bag has been limited to the inflation of the contours and has not been used to replace the stroke of the cylinders, as described above.
It is known that the above conventional-type automatic vehicle seats are unpopular because of the high cost of production due to the use of expensive drive-sources. For example, the use of cylinders requires pumps and motors. In addition, the total weight of these mechanisms is not negligible. Thus, the mechanisms have the disadvantage of increasing the weight of the car, which is contrary to energy conservation. Further, the conventional mechanisms have the disadvantage that the car occupant sitting on the seat is uncomfortable when the seat is being adjusted because the cylinders are mechanically driven to thrust out their contour pads or to excessively change the position of the seat. Also, the seat position and seat contour are made of a metallic construction without any cushion on the mechanism. It is known that the conventional vehicle seats have the disadvantage that some of them are not equipped with an automatic system for automatically locking the seat body after the position of the seat body has been changed. Without automatically locking, the vehicle seat has the disadvantage that the seat can be moved by an external cause, such as the sudden stop of the car or a car crash and, thus, the vehicle seat has serious safety problems.